1. Field of the Invention
The present invention relates to building entrance protectors for telecommunication lines. More particularly, the present invention relates to the wiring systems used for positioning fusible links within building entrance protectors.
2. Description of the Prior Art
Building entrance protector (BEP) is the name used in the art of telephone equipment to describe the junction box where telephone lines from outside plant wiring are joined to customer premises equipment. In the most common application, the BEP is the place where the telephone lines from a telephone pole, for example, enter a building and are joined to the telephone system within that building. Within the BEP there is an input wire termination device that receives the telephone lines contained within the outside plant wiring. Also contained within the BEP is an output wire termination device that receives the telephone lines required for the customer premises equipment. Located in between the input wire termination device and the output wire termination device are fusible links. The fusible links are typically 26 gauge copper wire, which is thinner than the gauge of either the outside plant wiring or the customer premises equipment.
The purpose of the fusible links is to prevent power surges from passing through the BEP that can damage equipment located within the building or melt any wire on the customer side of the BEP. Since telephone lines are typically strung on the same poles as power lines, a break in a power line that subsequently contacts a telephone line, can result in a large surge of power passing through the telephone lines into a building. Similarly, lightning strikes can result large surges of power pass in through telephone lines into a building. The purpose of the BEP is to ensure that any such power surge is stopped at the point of the BEP and is prevented from traveling into the building where it can cause damage to equipment and possibly a fire.
Referring to FIG. 1, a typical prior art BEP 10 is shown. From FIG. 1, it can be seen that as the outside plant wiring 12 passes into the BEP 10, the outside plant wiring 12 passes into a sealed, fire-resistant splice chamber 14. Within the splice chamber 14, some of the telephone wires contained within the outside plant wiring 12 are joined to fusible links 16, via an input wire termination device 18. Each set of the fusible links 16 leads to a different surge protector port 20 on a surge protector panel 22. The different surge protector ports 20 are coupled to an output wire termination device 24, wherein the customer premises equipment connects to the output wire termination device 24.
The fusible links 16 can connect to the outside plant wiring in a number of different ways. Individual wires can be separately joined together. However, such interconnections are highly labor and time intensive. The preferred interconnection mechanism is an input wire termination device 18 such as a terminal array connector. In FIG. 1, the shown terminal array connector 28 is exemplary of the model S 66 M connector manufactured by the Siemens Company.
Referring to FIG. 2, it can be seen that the fusible links 16 are connected to the terminal leads 26 on the bottom of the terminal array connector 28 and the outside plant wiring 12 is connected to the terminal leads 30 on the top of the terminal array connector 28. The fusible links 16 extend through a narrow hole 32 in the wall of the splice chamber 14 and connect to terminals 34 on the bottom of the surge protector panel 22. Should any of the fusible links 16 melt, the severed section of the melted fusible link must be repaired. If the fusible link 16 is severed within the splice chamber 14, the terminal array connector 28 is moved to expose the below lying fusible links 16. The defective portion of the fusible link 16 is cut away and replaced with a new spliced segment of fusible link. The terminal array connector 28 is again set into position and the BEP 10 is ready for use.
In many instances, when a fusible link 16 melts, it causes other fusible links within its vicinity to also melt or otherwise become damaged. These secondary melted and/or damaged fusible links must also be repaired. If a fusible link 16 were to melt and sever at a point under the surge protector panel 22, the fusible link 16 can not be readily repaired. It then becomes more cost effective to replace the entire BEP 10 rather than to effect repairs.
A need therefore exists for a BEP where the fusible links are part of a modular wiring system that allow all of the fusible links to be removed and replaced as a unit without replacing or otherwise affecting the remaining components of the BEP.